Microfilm projection apparatus

ABSTRACT

A transparent rotatable cylinder having spaced support flanges and seats therein for supporting a strip of microfilm and the like a small distance from the cylinder while the microfilm is being projected onto an image plane. A projector lamp is located adjacent the cylinder on the side of the cylinder opposite the image plane to illuminate the microfilm as it is fed in a path concentric with the surface of the cylinder between the cylinder and the image plane.

United States Patent Blacker-t et al. I

[4 1 Mar. 28, 1972 [54] MICROFILM PROJECTION APPARATUS [72] Inventors:John E. Blackert; Harvey S. Towers, both of Webster, NY.

[73] Assignee: Xerox Corporation, Rochester, NY. [22] Filed: Aug. 13,1969 211 App], No.; 849,674

[52] U.S. Cl ..355/49, 355/45, 355/11, 353/26 [51] Int. Cl. ..G03l 27/46[58] Field ofSearch ..353/26; 355/44, 45, 47,48, 355/49 [56] ReferencesCited 1 UNITED STATES PATENTS 2,347,938 5/1944 Dimmick ..355/4s2,130,562 10/1938 Pratt ..353/26 2,532,542 12/1950 dAvitaya.. ..355/482,939,362 6/1960 Cole ..35s/47 Primary Examiner-Samuel S. MatthewsAssistant Examiner-E. M. Bero Attorney-Donald E. Daley, James J.Ralabate and Terry J. Anderson [57] ABSTRACT A transparent rotatablecylinder having spaced support flanges and seats therein for supportinga strip of microfilm and the like a small distance from the cylinderwhile the microfilmis being projected onto an image plane. A projectorlamp is located adjacent the cylinder on the side of the cylinderopposite the image plane to illuminate the microfilm as it is fed in apath concentric with the surface of the cylinder between the cylinderand the image plane.

I Claims, 3 Drawing Figures PATENTEDMAR28 m2 IN VENTOR. JOHN E. BLACKERTARVEY s. TOWERS BY ATTDRNEV BACKGROUNDOF THE INVENTION This inventionrelates generally to reproducing microfilm images, and moreparticularly, to a device for supporting and driving a strip ofmicrofilm and the like while the information thereon is being projectedonto a photosensitive member.

One of the most widely used techniques presently employed to store largequantities of information in a relatively small space is to maintainsuch information on strips of microfilm. These strips, which can be madeof a photosensitive material such as photographic film and can be rolledinto a compact reel for storage, contain a multitude of individual imageframes, each of which can accommodate a reduced size image of oneor manyoriginals. When information is stored in this manner, a copy of theoriginal can be reproduced quite easily as needed from the microfilmstrip by merely projecting the particular image frame desired onto aphotosensitive member and processing the member to make the imagevisible and permanent. In reproduction systems such as those employingthe xerographic process, the apparatus can be made continuous andautomatic by using a photosensitive member in the shape of a drum whichis rotatable through the exposure station.

Due to the wide use of microfilm as a data storage method, ordinarycopying machines such as those used in the business office environmenthave been adapted to reproduce information on microfilm as well asreproduce original documents. In such duo-input copiers, one system ofreproduction can be used to copy in both modes of input, microfilm andoriginal documents, by positioning each mode of input so that a lightimage formed from it can be aligned with the exposure station of thephotosensitive member. There are many known.

scanning systems which are able to scan an original document andsynchronously place a light image of it onto the moving photosensitivedrum. However, there is a great need for a reliable and simpleprojecting system which synchronously projects a microfilm image onto aphotosensitive drum and at the same time is compatible with an originaldocument scanning system in the same copier.

Microfilm has been projected while moving the strip across a flat,transparent, stationary platen. A disadvantage of this system ofprojection is that elaborate and expensive control apparatus must beutilized to assure that the movement of the microfilm strip issynchronously timed with the movement of the photosensitive member. Afurther problem with this type of arrangement is that, as the microfilmstrip moves relative to the platen, it accumulates a charge on itssurface from continuously contacting the platen. This charge, in turn,attracts foreign matter onto the film surface which can reproduce ontothe copy sheet, and further, can injure the film when it is rewound intoa roll for storage.

SUMMARY OF THE INVENTION Accordingly, it is an object of the inventionto improve reproduction apparatus which makes copies from microfilm andthe like.

It is another object of the invention to improve microfilm projectionapparatus by supporting the strip of microfilm on a transparent cylinderassembly during projection.

It is another object of the invention to improve microfilm projectionapparatus by minimizing contact between the microfilm and its supportapparatus during projection.

It is another object of the invention to improve microfilm reproductionapparatus by moving the microfilm support apparatus at the same speed asthe photosensitive member in the reproduction apparatus duringprojection.

It is another object of the invention to improve microfilm projectionapparatus by providing a simple, reliable and inexpensive apparatus tosynchronize a light image projected from a strip of microfilm with arotating photosensitive drum.

These and other objects of the invention are attained by a rotatabletransparent cylinder having two spaced flanges thereon which support andcontrol the movement of a strip of 7 microfilm as it is being projectedonto a rotating photosensitive drum in a reproduction system. Theflanges on the cylinder are spaced a distance approximately equal to thewidth of the strip of microfilm and contain a seat in which the edge ofthe microfilm is placed to support it at a small distance from thesurface of the cylinder. The movement of the strip of microfilm throughthe projection apparatus is controlled by the movement of thetransparent cylinder and take up and storage spools. The transparentcylinder is rotatable on the same axis as the photosensitive drum andthrough a clutch device can be made to rotate with the photosensitivedrum to synchronize the movement of the light image formed from themicrofilm with the movement of the drum surface. The spools operate incooperation with the rotation of the transparent cylinder when themicrofilm is being projected to apply tension to the microfilm in thevicinity of the transparent cylinder to assure that there issubstantially no relative movement between the transparent cylinder andmicrofilm.

Other objects of the invention will become readily apparent to thoseskilled in the art in view of the following detailed disclosure anddescription thereof, especially when read in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration ofthe invention in a duoinput reproduction system.

FIG. 2 is an end view of the microfilm support device.

FIG. 3 is a section view of the. microfilm support device taken throughsections 3-3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The projection apparatusdescribed herein can be used with any reproduction system wherein astrip of microfilm, or the like, is projected onto a photosensitivemember; however, for the purpose of this disclosure, the microfilmprojection apparatus is described within the environment of axerographic copier which is adapted to copy both microfilm and originaldocuments.

FIG. 1 is a schematic illustration of a copier which reproduces bothoriginal documents and microfilm. As can be seen in this figure,photosensitive drum 101, the element upon which the image to bereproduced is formed, is exposed to a light pattern produced by eithermicrofilm projecting apparatus 200 or original document scanningapparatus 400 by selectively positioning mirror 209. When mirror 209 isin the position shown in solid lines, a light image formed by themicrofilm projecting apparatus 200 is exposed onto the photosensitivedrum 101 to the exclusion of any light image simultaneously produced byscanning apparatus 400. In the alternative, when mirror 209 is in theposition shown in dotted lines, a light image formed by the scanningapparatus 400 is exposed onto the drum 101 to the exclusion of any lightsimultaneously formed on the microfilm projecting apparatus 200. Theposition of mirror 209 can be selected manually by the operator of thecopier by a handle (not shown) extending from the mirror to the outsideof the machine, or can be adjusted automatically by any suitableapparatus (not shown) when the operator of the machine selects the modeof the operation of the copier to either microfilm or original documentreproduction. Although not shown in the drawings, the various elementsof the copier are mounted on a suitable frame member.

The reproduction system used in the copier can be any suitable typewhich utilizes a photosensitive member to form an image. For instance,the copying apparatus can be a xerographic system having anelectrostatic drum 101 and various xerographic processing stations (notshown) arranged about its periphery. For instance, the periphery of drum101 includes a photosensitive multilayer covering which comprises aphotoconductor material, such as vitreous selenium, over a suitableconductive material. The xerographic processing stations can be anyknown devices which allow the reproduction sure station where it isexposed stations. For simplicity, at the exposure station,

the microfilm to eliminate the possibility process to be carried outcontinuously. For example, these stations can include a chargingstation, exposure station, developing station, transfer station andcleaning station.

The photosensitive surface of drum 101 first passes through the chargingstation where it is given a uniform electrostatic charge. Then, thecharged surface passes through the expoto a light image formed fromeither the microfilm or original document input. This light imagedissipates the charge on the drum in the light areas to form a latentelectrostatic image on the drum conforming to the image beingreproduced. The latent image is then developed by the application of apigmented powder to the drum surface as it passes through the developingstation to make the latent image visible. Next, the powder image istransferred from the surface of the drum to a copy sheet which is fedfrom a supply of sheets onto the drum in the transfer station. Finally,charging station again, its surface is cleaned of any residue powder asit passes through the cleaning station.

Because the photosensitive member is in the shape of a drum, thereproduction processes described above can be carried out continuouslyas the drum rotates through the various FIG. 1 shows only aperture plate102,

and the photosensitive drum 101 of the xerographic system describedabove.As drum 101 rotates in the counterclockwise direction as indicatedby the arrow a light image passes through the plate and is exposed ontothe surface of the drum in synchronism with the movement thereof.

The reproduction system depicted in FIG. 1 is adapted to copy originaldocuments as well as microfilm by selecting the position of mirror 209.When mirror 209 is positioned as shown in dotted lines a light imageproduced by the scanning device 400 is directed through a lens andmirror system onto the drum 101. Scanning device 400 includes atransparent platen 404, upon which an original document 401 issupported, and a scanning mechanism 405 containing illuminating means toilluminate successive portions of the original document as the mechanismmoves in the direction shown by the arrow. Any suitable mechanism (notshown) can be employed to support the scanning mechanism as it is drivenacross the platen by motor MOT-4. The light image created by thescanning mechanism 405 is reflected by mirror 402 through focusing lens403 and then reflected by mirror 209 through the aperture plate and ontothe surface of drum 101. Focusing lens 403 is also supported on atranslating mechanism (not shown) to move relative to the platen 404 intimed relation to the movement of drum 101 and the illuminating portionof scanning mechanism 405 to project a flowing image of the originaldocument 401 onto the surface of drum 101.

The microfilm copying capability of the reproduction system shown inFIG. 1 is attained by employing microfilm projection apparatus 200. Theterm microfilm is used as a generic term herein, and encompasses anytype of information storage device which can be projected to form alight image of the information thereon. For instance, the device can bea transparency which has transparent, or translucent background areaswith opaque image areas or, in the altemative, opaque background areaswith transparent image areas. The strip of microfilm and images createdthereon can be made by any suitable process such as by knownphotographic techniques; however, it is not intended that the process belimited to photographic techniques.

, The projection apparatus 200 contains a microfilm support device 110and an illuminating device 201 which, respectively, supports andprojects the microfilm to form a light image of the information on themicrofilm. The illuminating device includes any suitable light sourcesuch as lamp 202, a condensing lens system made up of lenses 203, 205and 206 which focus the light produced by lamp 202 on the microfilm,filter 204 which prevents light in the infrared range from reaching ofdeleteriously overbefore the drum surface passes through the heating themicrofilm during illumination, and housing 207 which encloses all theelements mentioned above.

The microfilm support device 110 is located adjacent the illuminatingdevice 201 and includes a transparent rotatable cylinder having twoflanges which support the microfilm during illumination. The microfilmstrip is transported to and from the support device by a spool-to-spoolarrangement. During projection the film is fed in the direction shown bythe solid arrow in FIG. 1 from spool 301 onto the support device andthen to spool 307. The microfilm is supported by the support device 110so that light from the illuminating device projects the information onthe microfilm towards focusing lens 207. The light image passes throughenlarging lens 211, onto mirror 208, and onto mirror 209, which finallyreflects it to the surface of the photosensitive drum 101. The enlarginglens magnifies the image projected onto the photosensitive drum so thatthe copy produced is the same size as the original information placed onthe microfilm. The diameter of the transparent cylinder with respect tothe diameter of the photosensitive drum determines the ratio ofmicrofilm speed to drum surface speed and thus determines imagemagnification. For example, the diameter of the photosensitive drumshown in FIG. 1 is approximately 7.942 inches andthe diameter of themicrofilm support device ll0'is approximately 1.182 inches. Themicrofilm itself is approximately 0.004 inch thick, therefore, the imageis projected at a diameter of approximately 1.19 inches. In this case,the magnification of lens 211 should be 6.67X the same'as the ratio ofthe two diameters.

A more detailed view of the microfilm support device 1 10 is shownin'FIGS. 2 and 3. Referring to FIG. 2, transparent cylinder 104 issupported and driven by shaft 103 when the microfilm is being projected.The cylinder is preferably transparent to permit light from illuminatingdevice (not shown in this figure) to readily pass through it to themicrofilm. Mounted securely about the periphery of the cylinder are tworing-shaped support flanges 106 which turn with the cylinder and supportthe microfilm a small distance above the surface of the cylinder. As canbe seen in FIG. 3, each flange has a seat 107 positioned on the side ofthe flange nearest the center of the cylinder so that the seats faceeach other. The microfilm is supported on the seats while beingilluminated thereby minimizing the area of contact between the surfaceof the microfilm and the support device during projection. The seats areplaced sufficiently far apart to allow the microfilm strip to be fedonto and removed from the flange with ease as the cylinder turns.

The microfilm strip is supported a small distance from the periphery ofthe cylinder rather than in contact therewith in order to keep thesurface of the microfilm free of charge. If the microfilm strip ispermitted to contact the surface of the cylinder it has been found thata charge builds up on the microfilm material. As a result of this chargebuild up, foreign matter is attracted to the film surface and thepresence of such foreign matter is undesirable since it could be groundinto the microfilm material to cause scratching and excessive wearthereto, especially as the microfilm is wound around the spool. Inaddition, the foreign matter would reproduce onto the copy sheet andcause background on the reproduction.

Referring to FIG. 2, the strip of microfilm is wrapped aroundapproximately half the periphery of the microfilm support device 110.Since only that portion of the microfilm adjacent field lens 113 isactually being projected onto the photosensitive drum, the strip ofmicrofilm must necessarily be located in the seats of the flanges 106 atleast in this vicinity. However, to be certain that the strip ofmicrofilm is properly seated adjacent the field lens, and that there isadequate surface contact between the flanges and microfilm to assure asteady, positive driving force on the strip by the support device, thestrip is preferably maintained in contact with as much as the flangeperiphery as practical without blocking the illumination passing throughthe cylinder. This condition is shown in FIG. 2. The angle of wrap ofthe microfilm strip is ultimately determined by the positions of guiderollers 303 and 304 which hold the strip the support device.

In addition to the elements described above, the support device alsocontains a microfilm detection device which is employed to read codemarks on each microfilm frame so that a copy sheet can be fed to thetransfer station of the drum 101 (shown in FIG. 1) in synchronizationwith the image on the drum. Code marks on the microfilm and thedetection device must be compatible with each other. For instance, acode 114, in this case a transparency pattern, can be placed in theleading portion of each frame on the strip of microfilm as shown in FIG.3. This code pattern can be detected by a lamp and photocell arrangementsuch as that shown in FIG. 2. The code tightly against can be anysuitable type which can be detected by a lamp and photocell arrangementsuch as a series of opaque dots and areas at the leading edge of theframe. When this type of code is used in the frames, the code scannermust be distinguished between the code and the image. This can be doneby selecting a code which has an extremely low probability of being seenin the image. A strip of microfilm can have several bits of informationon it such as a code to indicate the leading edge of Y the strip, thetrailing edge of the strip,

a code for each frame on the strip to synchronize the feeding of thecopy sheet, etc.

' The code detection device shown is a lamp 111 located inside thetransparent cylinder and a bank of photocells adjacent the path of themicrofilm strip. As a code on a particular frame passes between the lampand the bank of photocells,

the pattern of opaque areas in the code produce a corresponding lightpattern which activates selected photocells in the bank. The signalproduced by the bank of photocells can then be used to start the feedingof the copy sheet toward the transfer station-of the drum 101.

The operation of the apparatus during each microfilm strip reproductioncycle includes two general phases; a take up phase and an imaging phase.Referring to FIG. 1, the microfilm strip is wound at a relatively fastrate of speed in the direction shown by the broken arrow from thestorage spool 307 to the take up spool 301 during the take up phase inpreparation for the imaging phase. Then, during the imaging phase, themicrofilm strip is fed in the direction indicated by the solid arrowfrom the take up spool back towards the storage spool at a rate of speedsynchronous with the speed of drum 101. Take up spool 301 is permanentlyattached to the copier and is driven through shaft 302 in the clockwisedirection as shown by the arrow by motor MOT-2 while storage spool 307,which is removable from the copier, is driven through shaft 308 in thecounterclockwise direction, as shown by the arrow, by motor MOT-3.

The first step in using the copier in the microfilm reproduction mode isto place a spool 307 of microfilm on shaft 308 and feed the leading edgeof the strip through the opening 312 in the housing 306, the other endof the strip being attached to the spool. Then, a leader strip (notshown in the figure), which is permanently attached to spool 301 at oneend, is fed between guide roller 303 and microfilm support device 110,around the periphery of the device, between the cylinder and guiderollers 304 and over the roller 305 to the vicinity of opening 312. Thefree end of the leader strip is adapted to be removably joined to theleading edge of the strip of microfilm by any suitable arrangement suchas a simple manual splice (not shown), and is employed to guide themicrofilm strip through the projection apparatus during the take upphase of the operation.

During the take up phase, motor MOT-2, an AC motor is operated at itsrated speed to wind the microfilm around spool 301 at arelatively fastrate while motor MOT-3, a DC motor, provides a slight drag on themicrofilm strip. Clutch 105, which joins the microfilm support device110 to the shaft 103 of drum 101, is disengaged during the take up phaseso that the microfilm support device 110 can turn freely at this time.After all the frames to be reproduced have traveled over the supportdevice 110 and are located on the take up spool side of the supportdevice, the imaging phase can begin. As mentroned above, code marks onthe microfilm strip indicate when .phase in response to the code. Thefilm is stopped with a minimum overshoot by dynamically braking motorMOT-3 and allowing the inertia of motor MOT-2 to provide a force on thestrip in the direction to maintain tension on it.

During the imaging phase, clutch is engaged and the transparent cylinderand photosensitive drum turn together. During this time motor MOT-3drives spool 307 at a slower speed than spool 301 is driven during thetake up phase to carry each frame in the strip over the microfilmsupport device for projection. The speed of the spool 307 during theimaging phase is such that the microfilm strip and transparent cylindermove together at the same speed through the light generated by lamp 202.Synchronism between the movement of the strip of microfilm 300 and thedrum 101 is attained due to the fact that the strip moves at the samespeed as the transparent cylinder and the cylinder, in turn, moves atthe same speed as the drum 101 since clutch 105 is engaged. During theimaging phase, a DC current is placed on motor MOT-2 which acts as adrag or tension force on the strip of microfilm. This drag forceequalizes the tension on the strip 300 on both sides of the microfilmsupport device 110 to assure that the microfilm remains synchronizedwith the cylinder during projection.

It is intended that appropriate drive means and control devices beassociated with the copying system described herein, however, eachspecific drive means and control device is'not described in detail sinceany suitable type can be used which would allow the system to functionas described above.

In addition to the apparatus outlined above, many other modificationsand/or additions to this invention will be readily apparent to thoseskilled in the art upon reading this disclosure, and these are intendedto be encompassed within the invention disclosed and claimed herein.

What is claimed is:

1. In a reproduction system having a drum with a photosensitive surfacesupported on a drum shaft which is rotatable in a frame, an exposurestation adjacent the photosensitive drum at which a light image ofinformation to be reproduced is exposed onto the surface of the drum toproduce an image thereof, and means to rotate the drum shaft to bringsuccessive portions of the drum surface through the exposure station,apparatus for projecting microfilm information onto the photosensitivesurface of the drum comprising:

a. a rotatable transparent cylinder adapted to transmit illu minationtherethrough and supported by a cylinder shaft having a centerlinccoincident with that of the drum shaft;

b. means to connect the cylinder shaft to the drum shaft so that thecylinder and drum rotate together;

0. support means on the cylinder adapted to support the strip ofmicrofilm at a gap from the surface of the cylinder;

d. illumination means adjacent the cylinder on the side of thecenterlines of the cylinder and drum shafts opposite the exposurestation adapted to direct light through the cylinder;

e. a system of reflectors to reflect the light which passes through thecylinder to the exposure station;

. means to position the microfilm strip on the supporting means betweenthe support means and system of reflectors; and

g. control means to connect the cylinder shaft and drum shaft duringprojection. of the microfilm so that the cylinder and drum rotatetogether thereby attaining synchronization between the movement of themicrofilm and drum surface.

1. In a reproduction system having a drum with a photosensitive surfacesupported on a drum shaft which is rotatable in a frame, an exposurestation adjacent the photosensitive drum at which a light image ofinformation to be reproduced is exposed onto the surface of the drum toproduce an image thereof, and means to rotate the drum shaft to bringsuccessive portions of the drum surface through the exposure station,apparatus for projecting microfilm information onto the photosensitivesurface of the drum comprising: a. a rotatable transparent cylinderadapted to transmit illumination therethrough and supported by acylinder shaft having a centerline coincident with that of the drumshaft; b. means to connect the cylinder shaft to the drum shaft so thatthe cylinder and drum rotate together; c. support means on the cylinderadapted to support the strip of microfilm at a gap from the surface ofthe cylinder; d. illumination means adjacent the cylinder on the side ofthe centerlines of the cylinder and drum shafts opposite the exposurestation adapted to direct light through the cylinder; e. a system ofreflectors to reflect the light which passes through the cylinder to theexposure station; f. means to position the microfilm strip on thesupporting means between the support means and system of reflectors; andg. control means to connect the cylinder shaft and drum shaft duringprojection of the microfilm so that the cylinder and drum rotatetogether thereby attaining synchronization between the movement of themicrofilm and drum surface.